This invention relates to new sulfurized compositions of matter which are suitable particularly for use as lubricant additives, and to methods for their preparation. More particularly, the sulfurized compositions of the invention are derived from a mixture of at least one terpene compound and at least one other olefinic compound.
Compositions prepared by the sulfurization of various materials including olefins are known in the art, and lubricants containing these compositions also are known. Typical sulfurized compositions prepared by reacting olefins such as isobutene, diisobutene and triisobutene with sulfur under various conditions are described in Chemical Reviews, 65, 237 (1965), and in The Chemistry of Organic Sulfur Compounds, Vol. II, Chapter 10, (1966). These products generally are characterized by the presence of a trithione grouping. A by-product is hydrogen sulfide, and it is frequently taught that it is desirable to remove the hydrogen sulfide which is formed. Other publications describe the reaction of such olefins as isobutene, diisobutene and triisobutene with hydrogen sulfide to form predominantly mercaptans, and by-products such as sulfides, disulfides and higher polysulfides. See, J. Am. Chem. Soc., 60, 2452 (1938); J. Chem. Soc., 1947, 1532; and U.S. Pat. Nos. 3,221, 056 and 3,419,614.
U.S. Pat. No. 4,191,659 describes the preparation of sulfurized olefinic compounds by the catalytic reaction of sulfur and hydrogen sulfide with olefinic compounds containing from 3 to 30 carbon atoms. Such compounds are reported to being useful in lubricating compositions, particularly those prepared for use as industrial gear lubricants. U.S. Pat. No. 4,119,549 describes a similar procedure for sulfurizing olefins utilizing sulfur and hydrogen sulfide following by removal of low boiling materials from said sulfurized mixture.
Other sulfurized compositions of matter also have been suggested as compositions useful as additives for lubricants. U.S. Pat. No. 2,012,446 describes a method of sulfurizing pine oil which is reported as being useful as an additive for lubricant manufacture. U.S. Pat. No. 3,953,347 describes a sulfurized composition matter which is prepared by reacting sulfur with a mixture of at least one fatty acid ester of a polyhydric alcohol, at least one fatty acid and at least one aliphatic alpha-olefin. These latter compositions are suitable as replacement for sulfurized sperm oil as extreme pressure additives in lubricants.